Six key threatening processes of rivers and streams

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee on public nominations of Key Threatening Processes under the Environment Protection and Biodiversity Conservation Act 1999

1. Names and descriptions of the threatening processes

The names provided for the six nominations are:

  • 'Alteration to the Natural Flow Regimes of Rivers and Streams'
  • 'Alteration to the Natural Temperature of Rivers and Streams'
  • 'Increased Sediment Input to Rivers and Streams Due to Human Activities'
  • 'Introduction of Live Fish into Waters Outside their Natural Range after 1770'
  • 'Removal of Large Woody Debris from Rivers and Streams'
  • 'The Prevention of Passage of Aquatic Biota as a Result of the Presence of Instream Structures'

The TSSC considers the names and descriptions provided to be inadequate to appropriately identify and define the processes, and thus allow assessment. A summary of the reasons for this conclusion is provided in attachment (i).

2. How judged by TSSC in relation to the Environment Protection and Biodiversity Conservation Act 1999 criteria

A. Could the threatening process cause a native species or an ecological community to become eligible for listing as Extinct, Extinct in the Wild, Critically Endangered, Endangered or Vulnerable?

B. Could the threatening process cause a native species or an ecological community to become eligible to be listed in another category representing a higher degree of endangerment?

C. Does the threatening process adversely affect 2 or more listed threatened species (other than conservation dependent species) or 2 or more listed threatened ecological communities?

As the names and descriptions are inadequate to appropriately identify and define the threatening processes, assessment of evidence of impacts is difficult. In addition, the nominations contain general information on the nature of threat, but little evidence relating to the level of impact on particular species or ecological communities, or on the processes potentially causing listed or unlisted species or ecological communities to meet the thresholds for listing in categories representing a higher degree of endangerment. A summary of the reasons for this conclusion is provided in attachment (i).

Conclusion - Based on the non-specific nature of names and descriptions, and insufficient evidence of the impact of the processes, the TSSC considers that the nominations do not contain sufficient information to determine if the processes:

  • could cause a native species or an ecological community to become eligible for listing in any category, other than conservation dependant;
  • could cause a listed threatened species or a listed threatened ecological community to become eligible to be listed in another category representing a higher degree of endangerment; and
  • is adversely affecting 2 or more listed threatened species (other than conservation dependant) or 2 or more listed threatened ecological communities.

The threatening processes do not meet s188(4)(a), s188(4)(b), or s188(4)(c) of the EPBC Act.

3. Recommendations

A. TSSC recommends that the following nominations:

  • 'Alteration to the Natural Flow Regimes of Rivers and Streams'
  • 'Alteration to the Natural Temperature of Rivers and Streams'
  • 'Increased Sediment Input to Rivers and Streams Due to Human Activities'
  • 'Introduction of Live Fish into Waters Outside their Natural Range after 1770'
  • 'Removal of Large Woody Debris from Rivers and Streams'
  • 'The Prevention of Passage of Aquatic Biota as a Result of the Presence of Instream Structures'

could not be assessed and are not eligible at this stage for listing as Key Threatening Processes under the EPBC Act.

B.The TSSC intends to follow up ways to improve the nominations with the nominator.

Attachment (i) Review of information provided and reasons for rejection of the individual nominations

All nominations:

  • The terms 'rivers' and 'streams' are not defined and are not prescriptive- the term 'watercourse' is less arbitrary, more commonly used, and defined in most State legislation.
  • There is no information on the processes potentially causing listed or unlisted species/communities to meet the thresholds for listing in categories representing a higher degree of endangerment.
  • There is no information on the level to which the threat to any species/community is mitigated or where.

'Alteration to the Natural Flow Regimes of Rivers and Streams'

  • Twenty seven species and three communities are included in the nomination. The description and further information sections explain general information on the threats to fish, marine environments, invertebrates, wetland areas, birds, and riverine ecosystems.
  • A small amount of information is provided (in the form of citations from the literature) on the impacts for six of the twenty seven species, and for wetland plant communities included in the nomination (including two threatened species). There is no information relating to the degree of threat. Mitigating actions underway are described.

'Alteration to the Natural Temperature of Rivers and Streams'

  • The description includes information on cold water discharge from dams, and increased temperature from riparian vegetation removal and urbanisation. The section on Threat Abatement states these 'two threatening processes need to be considered together'. However, only general information is provided on the effects of increases in temperature on invertebrates and algae, while the information provided on threats to specific fish species relates to cold water pollution only. Cold water pollution occurs only in rivers that have large dams, while temperature increases due to remnant vegetation clearing and urbanisation can occur in all watercourses.
  • Twenty four species and one community are included in the nomination. The description and further information sections explain general evidence for threats on fish, invertebrates and algae. Information on the effects of cold water pollution only is provided for six of the twenty four species included in the nomination (two of which are listed threatened). Possible mitigating actions are described.

'Increased Sediment Input to Rivers and Streams Due to Human Activities'

  • The description of human activities is not adequate - it is not clear whether the list of activities provided is definitive, since other practices which can increase sedimentation are not included. For example agricultural activities, storm water, dam operation, and stock access are included in the Threat Abatement Section but not the description.
  • Twenty six species and one community are included in the nomination. The description and further information sections explain general evidence for threats on fish, invertebrates and frogs. Information on effects is provided for three of the twenty six species included in the nomination (including two listed threatened). There is no information relating to the degree of threat. Mitigating actions underway are described.

'Introduction of Live Fish into Waters Outside their Natural Range after 1770'

  • It is not clear from the title whether the date 1770 relates to fish introductions. The Victorian Flora and Fauna Guarantee Act 1988 lists 'Deliberate or accidental introduction of live fish into public or private waters within a Victorian river catchment in which the taxon to which the fish belongs cannot be reliably be inferred to have been present prior to the year 1770 AD' as a potential threatening process. Since abatement of the threat of introduced fish could include both restrictions on future introductions and management of previously introduced fish, a more succinct and appropriate title should be used (such as 'Fish introduced to river catchment waters outside their natural range').
  • The term 'natural range' is not defined.
  • The description includes the introduction of native and exotic fish, however the information provided on impact relates to introduced exotic fish only.
  • Fifteen species and one community are included in the nomination, and the description and further information sections explain general information about threats on fish and frogs. A small amount of information is provided (in the form of citations from the literature) on the effects for nine of the fifteen species included in the nomination (five of which are listed threatened), plus a further threatened frog species (which is not included in the section naming listed species). The nomination mentions Recovery Plans for listed species and Commonwealth regulation of alien species introduction.

'Removal of Large Woody Debris from Rivers and Streams'

  • Large woody debris is defined as comprising 'trees, branches, leaves and other litter'.
  • Removal of woody debris is not defined - this could involve taking from the water, the bed, channel and/or floodway. The Conclusion and Threat Abatement Plan sections of the further information include minimal information on why woody debris is removed and who removes it.
  • The description and further information sections contain information on the use of large woody debris by fish and invertebrates, and general information on adverse effects of the process on fish, invertebrates and ecosystem processes. Twenty six species and one community are included in the nomination. Some information on the use of large woody debris is provided for 16 of the 26 species included in the nomination (including 4 threatened species). There is no information relating to the degree of threat. Mitigating actions underway are described.

'The Prevention of Passage of Aquatic Biota as a Result of the Presence of Instream Structures'

  • The description describes artificial structures and artificial barriers, while the name does not distinguish between artificial and natural structures.
  • Eighteen species and one community are included in the nomination. The further information section explains general information on the threats on fish and invertebrates. A small amount of information on migration or potential threat is provided for ten species (including three threatened species). There is no information relating to the degree of threat. Mitigating actions described include NSW legislation and guidelines, and Commonwealth programs